Energy conservation is crucial in wireless ad hoc sensor network design to increase network lifetime. Since communication consumes a major part of the energy used by a sensor node, efficient communication is important. Topology control aims at achieving more efficient communication by dropping links and reducing interference among simultaneous transmissions by adjusting the nodes’ transmission power. Since dropping links make a network more susceptible to node failure, a fundamental problem in wireless sensor networks is to find a communication graph with minimum interference and minimum power assignment aiming at an induced topology that can satisfy fault-tolerant properties. In this paper, we examine and propose linear integer programming formulations and a hybrid meta-heuristic GRASP/VNS (Greedy Randomized Adaptive Search Procedure/Variable Neighborhood Search) to determine the transmission power of each node while maintaining a fault-tolerant network and simultaneously minimize the interference and the total power consumption. Optimal biconnected topologies for moderately sized networks with minimum interference and minimum power are obtained using a commercial solver. We report computational simulations comparing the integer programming formulations and the GRASP/VNS, and evaluate the effectiveness of three meta-heuristics in terms of the tradeoffs between computation time and solution quality. We show that the proposed meta-heuristics are able to find good solutions for sensor networks with up to 400 nodes and that the GRASP/VNS was able to systematically find the best lower bounds and optimal solutions.
Energy conservation is crucial in wireless ad hoc sensor network design to increase network lifetime. Since communication consumes a major part of the energy used by a sensor node, efficient communication is important. Topology control aims at achieving more efficient communication by dropping links and reducing interference among simultaneous transmissions by adjusting the nodes’ transmission power. Since dropping links make a network more susceptible to node failure, a fundamental problem in wireless sensor networks is to find a communication graph with minimum interference and minimum power assignment aiming at an induced topology that can satisfy fault-tolerant properties. In this paper, we examine and propose linear integer programming formulations and a hybrid meta-heuristic GRASP/VNS (Greedy Randomized Adaptive Search Procedure/Variable Neighborhood Search) to determine the transmission power of each node while maintaining a fault-tolerant network and simultaneously minimize the interference and the total power consumption. Optimal biconnected topologies for moderately sized networks with minimum interference and minimum power are obtained using a commercial solver. We report computational simulations comparing the integer programming formulations and the GRASP/VNS, and evaluate the effectiveness of three meta-heuristics in terms of the tradeoffs between computation time and solution quality. We show that the proposed meta-heuristics are able to find good solutions for sensor networks with up to 400 nodes and that the GRASP/VNS was able to systematically find the best lower bounds and optimal solutions.
Different unexpected combinations between industry, local government, private participants, educational institutes and artists resulted past year in challenging opportunities for transitions in urban and rural areas. The power of art with the perspective of the artist approaching challenges evokes a chain of thoughts and (cascading) events, affecting systems. This results not only in innovative sustainable social &industrial products but also in change of systems. Panarchy is the paradigm of transition and change (Holling). Panarchy is interaction of countless interconnected and nested complex adaptive systems. Panarchy is the paradigm where small actions can have major effects for good or worse. It is to expect the unexpected. Panarchy holds the promise of positively changing the anthropocene. By being prepared we can anticipate upon unexpected emerging phenomena which can be used as leverage for creating change. SDG-labs are the environment where we can experiment and create new resilient concepts for adaptation to the antropocene. SDG-Labs have two aspects, the first is creation of concepts for change within the lab-setting, its content; the second is the process of organisation of the lab within its environmental and societal context. The Lab itself can be regarded as a complex adaptive system while the organisation of the SDG-Lab is within panarchy, acting on multiple levels and on different scales. Both faces, content and context, of the SDG lab have their own emerging properties. For facilitation of the SDG-lab we organised workshops where creative methods based upon TRIZ ("Theory of inventive problem solving") and CPS (Creative Problem Solving) were applied. TRIZ makes use of pre-established thinking patterns and proven abstract solutions to sets of abstract problems. TRIZ provides a toolbox for solving complex (wicked) problems. TRIZ uses the heuristics of intrinsic technological and societal evolution once a concept emerges. CPS is used for application of the TRIZ toolbox, by making concrete problems abstract and abstract solutions, concrete. TRIZ and CPS makes use of analytical and design thinking. Results of these workshops are emerged pre-concepts which have the potential to create change. Contextual settings of the SDG-lab determine its rate of success. Many good ideas perish in the “valley of death”, before they can realise their full potential. The contextual setting determines acceptance and hence increases probability of idea realisation. The action of organising SDG-labs generates curiosity, enthusiasm, resistance and other emotions with people and organisations. This lead to disturbances in panarchy, which is rendered in emerging opportunities that can be seized by imaginative people. Sarasvathy and Simon (2000) coined for this approach the concept of effectuation as an entrepreneurial principle for seizing opportunities which emerge from entrepreneurial actions in contrast to causation where managerial thinking obscures seeing opportunities. Effectuation is actor dependent where given specific means, choice of effect is driven by characteristics of the actor and his or her ability to discover and use contingencies. This approach is also recognised in innovation theory where the concept of “exaptation” is explored. Exaptation is the attribution of a new functionality to an existing artefact (or organization, scientific achievement, or
Veel mkb ondernemers maken gebruik van een financieel adviseur bij belangrijke financiële beslissingen. Momenteel is er echter weinig inzicht in achterliggende psychosociale factoren die het financiële advies van financieel adviseurs beïnvloeden. Op basis van eerder onderzoek (Kahneman, 2013) blijkt dat mensen zich laten leiden, als het gaat om financiële beslissingen, door een keur aan psychologische ‘denkvalkuilen’ (‘heuristics’ en biases’). Verondersteld wordt dat rol van de adviseur zou moeten zijn om specialistisch en objectief advies te geven, echter de denkvalkuilen en vooroordelen van de cliënt ‘klinken ook door’ in het advies van hun financieel adviseurs. Zo worden irrationele vormen van risicoperceptie en irreële verwachtingen van cliënten ten aanzien van de toekomst meegenomen in de adviezen van adviseurs; “de klant is immers koning.” Eerder onderzoek suggereert dat financieel adviseurs de verwachtingen en ideeën van hun cliënten alleen maar bevestigen en niet, indien nodig, bij irreële of ‘foute’ verwachtingen of aannames, corrigeren. De beweegreden van de adviseur hiervoor zijn dat meegaan met de ideeën van cliënten resulteert in minder verantwoordelijkheid voor de adviseur bij negatieve uitkomsten of resultaten; “dit is immers wat de cliënt zelf wil.” Terwijl veel input en advies het tegenovergestelde bewerkstelligt, “de cliënt vaart blind op de adviezen van zijn adviseur”, wat de cliënt-adviseur relatie in gevaar brengt bij negatieve resultaten. Het gevolg is een suboptimaal en in sommige gevallen slecht financieel advies. Dit onderzoek heeft tot doel de voorwaarden van een opener, beter afgewogen en objectiever financieel advies te ontdekken voor mkb-ondernemers, De centrale vraag is: Hoe komt een financieel adviseur tot een financieel advies voor mkb bedrijven? Deze vraag zal beantwoord worden de een survey bij de twee grootste franchise financiële advieskantoren (+/- 2500 leden), wat een representatieve steekproef is voor de financieel adviseurs in het mkb.
